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Microsoft Office SharePoint Elevation of Privilege Vulnerability

8.8HighCNA
Exploited
No known exploitation
Fix
Fixed in 16.0.20326.20136
Who is exposed
Not reported

Do first: Upgrade to a fixed version: 16.0.20326.20136.

Published
Last modified
Reference
Last checked
12/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

Incorrect authorization in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

cve.now Index

12Pcve.now Index 12 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure3/25Reachable over the network · Unknown: No advisory context yet
  • Reach?/20Unknown. No tracked technology or package matched
  • Severity8.8/10CVSS 8.8
  • No patch0/5No signal

What would change the score

  • Would score about 67 if added to CISA KEV
  • Would score about 62 if CISA's SSVC rates exploitation active
  • Would score about 31 if advisories confirm default setups are exposed

What to do

  • Upgrade to a fixed version: 16.0.20326.20136.

Check your systems with an agent

Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.

Check whether my systems are affected by CVE-2026-123391 (Microsoft Office SharePoint Elevation of Privilege Vulnerability), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-123391 (entry last updated 2026-11-10):
Affected:
- Microsoft Microsoft SharePoint Server Subscription Edition: from 16.0.0, fixed in 16.0.20326.20136
Fixed versions: 16.0.20326.20136.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-123391 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-123391 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-123391
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-123391
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-123391.

Timeline

  1. CVE published
  2. Record last updated
  3. First seen by cve.now

Affected versions

  • Microsoft Microsoft SharePoint Server Subscription Edition

    From 16.0.0 · fixed in 16.0.20326.20136

Evidence 3

Vendor advisory · 1

Establishes: Affected and fixed versions.

  1. Patch

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-123391

Is CVE-2026-123391 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-123391?

Microsoft SharePoint Server Subscription Edition: from 16.0.0 before 16.0.20326.20136.Source: cve.now feed data

How do I fix CVE-2026-123391?

Upgrade to a fixed version: 16.0.20326.20136.Source: cve.now feed data